Mexican American women are one of the most vulnerable and underserved populations at risk for obesity and Type 2 Diabetes (T2D). Utilizing a translation research paradigm, we propose to pilot a community-based, culturally sensitive T2D prevention program for high-risk Mexican American women, "Mujeres Interesadas en Cambios por la Salud" (MI CASA;Women Interested in Changes for a Healthy Lifestyle) in West Side San Antonio, Texas, a highly impoverished inner-city community. MI CASA is modeled after two successful programs that have been tested in randomized clinical trials (RCT), the U.S. Diabetes Prevention Program and the Finnish Diabetes Prevention Study - both primary care-based T2D prevention programs. MI CASA has been built upon the existing infrastructure of the Edgewood Family Network (EFN), a grassroots advocacy group for improving the well-being of residents in West Side San Antonio. MI CASA will be delivered by EFN's promotoras de salud (lay community health workers). Two hundred non-diabetic Mexican American females (ages 25 to 65), who have BMI 28 to 40, family history of T2D, and physical inactivity or who have previously diagnosed fasting glucose tolerance or gestational diabetes, will be recruited from a community hospital and randomized into intervention or comparison conditions after baseline testing. The proposed study hypothesizes that a promotoras-led lifestyle intervention will significantly reduce body weight, percent body fat, and fasting glucose and increase cardiorespiratory fitness in MI CASA participants at the end of the 9-mo intervention. We will also conduct an analysis of cost-effectiveness on the reduction of body weight and fasting glucose. A mobile health laboratory will be used to collect data in convenient locations in the community. Implementation of a structured, intensive lifestyle intervention by highly trained health professionals is cost-prohibitive to widespread dissemination. MI CASA primarily targets low cost, accessible forms of physical activity, and culturally sensitive healthy eating practices delivered by promotoras;if successful, it has the potential to be disseminated in underserved communities with limited resources. Program sustainability is enhanced by its connection with a community hospital and utilization of a community advocacy group for delivery, low cost equipment, and existing physical infrastructure. Little evidence exists regarding the effectiveness of promotoras-led lifestyle change programs in high-risk minority populations to reverse obesity and reduce risk for T2D. Thus, this study fits the goal of reducing the gap between bench/clinical research and health promotion at the community level in the NIH Roadmap for Medical Research. Finally, the proposed study addresses three (physical inactivity, overweight/obesity, and access to health care) of the 10 priority public health issues in Healthy People 2010. PUBLIC HEALTH RELEVANCE: The proposed study will pilot the feasibility of a promotoras-led lifestyle intervention program to lose weight and reduce risk for type 2 diabetes in high risk Mexican-American women. If successful, the low-cost intervention can be disseminated to underserved communities across country.